Recently, with the rapid development of mobile internet, portable devices such as tablet computers are more suitable for the concept of mobile internet. The market of tablet computers expands explosively. Tablet computers are advantageous in portability and capability of providing better audiovisual experiences. However, conventional operating systems for tablet computers are very limited. The operating systems for traditional computers are typically used, which are designed for mouse and keyboard based operations and cannot take advantages of touch operations and thus cannot meet consumer's requirements.